Process for selectively removing molybdenum from liquid mixtures containing it, in a quantity greater than (200) mg/l, together with vanadium characterized in that it comprises the following steps: bringing the liquid mixture to a pH of less than (3); adding a solution of an alkaline xanthate to the solution so that the molar ratio molybdenum/alkaline xanthate ranges from (1/4) to (1/8), maintaining the pH constant by means of the addition of an inorganic acid; stirring the mixture causing the precipitation of the molybdenum present in the mixture.